Glass-lined head for tanks



FIG

Francis Wi Lanci( INVENTOR:

y ATTORNEY Nov. 23, 1943. F,- w. LAUCK GLASS LVINED HEAD FOR TANKS Filed April 25, 1942 Fig. 2 is an enlarged one side oi the head and shellA assembled ready Patented Nov. 253, 1943 Francis W. LauckyMilwaukee, Wis., assignor to A. 0. Smith Corporation, Milwaukee, Wis., a corporation of New York Application April 25,' 1942, Serial No. 440,426

3 Claims. ('Cl. 220-64) This invention relates to glass -lined heads for tanks and has foundk practical application in thel construction of domestic hot water storage tanks having ceramic enamel linings.

In the construction of such tanks it is the better ypractice to line the heads and shell separately before assembling and welding, as set forth in the Letters Patent No. 2,263,021 granted to Otto Uecker on November 18, 1941. In such construction the heads have an outwardly extending iiange'joined to the central pressure retaining portion'of the head by a curved knuckle portion of substantial radius. The outer end oi the flange is Welded to the end edge of the shellto complete the closure.

Cil

The shrinkageof the weld in cooling down" has atendency to redu'ce the radius of the outer end knuckle radius ofthe head. This tendency results in a prestressed condition in the knuckle of the head, which, when the working stress of the flange and to thereby tend to reduce the from internal iluid pressure is added and the head is suiiiciently thin, may result in a move--y ment in ,the head that crazes or injures the enamel lining of the head.

The principal object of the invention is to eliminate the stress caused heretofore by shrinkage of the Vweld so that there is' less danger of injury to the enamel under working loads.

Another object is to utilizethe shrinkage of the weld to more tightly seal the overlapping contacting surfaces of the shell and the head flange which constitute the approach to the wel for the liquid contents of the tank. e

Another object is to control and localize the stresses resulting from4 shrinkage of the weld at points remote from stresses resulting from working pressures in the tank. f

VAnother object is to provide for the safe employment of thinner metal wallsfor the heads of the tank.

Other objects will appear hereinafter in connection with the description of the preferred embodiment of the invention illustrated in the accompanying drawing.

I In the drawing: l

Figure l is a vertical central longitudinal vsecby weld shrinkage exaggerated' for illustrative purposes.

The tank comprises a cylindrical shell l and- Iupper and lower heads `2 and 3 having reverse iianges 4 inserted in the ends of the shell and welded thereto at the adjacent outer ends of the flanges and shell.

heads and shell prior to assembly. The lining on the outer` surfaces of 'the circumferential iianges of the heads overlaps the lining of the shell for a substantial distance either with or without a packing material therebetween. The heads 2 and 3 are formed from fiat sheets of metal. upward or outward crown 6 which is joined to its circumferential flange 4 by acurved knuckle 'l constituting a reverse bend. The lower head 3 preferably has an upward or inward crown 8 joined to its circumferential iiange l by an ordinary curved knuckle 9.

'I'he heads 2 and 3 are joined to the respective end ledges of the shell by circumferential arc `Welds l0.

In order to preventstresses from up in theknuckles 'I and 9 by reason of the shrinkage of the welds, each of the ilangs l is provided vof lthe heads.

the weldand between it and the main body ci' the head. The slots may be located on the enamvlith a circumferential slot Il preferably on the exposed side of the ilange opposite the weld Ill.l

The slots Il should extend a suiilcient distance through the thickness of the ilanges I to provide a line of bending weakness where the shrinkage of the weld can bend the outer ends of the flanges inwardly as shown in Fig. 3 without bending the.

main body of the flanges or stressing the knuckles The slots I l should be located near eled side of the flanges, i! desired.

tion through a domestic hot water tank with `parts broken' away;-

sectional viewl showing for welding; and

.Fig. 3 isa similar sectionalview'showfina the y 'j V- Y parts afterfwelding with the movement I5 Various em ents o! thefinvention 'of-the head inservice.

The shrinkage of the weld l0, as it heur-is the end of the flange 4 inwardly, draws the end of the shell. inwardly to make a tighter contactbetween it and that part of the head flange between the siot Il and the head knuckle, as illustrated by -comparing Figs. 2 and 3. This more adequately seals the approach to the weld metal from the inside and prevents the liquid contents` of the tank from circulating in contact with the weld and corroding the same. The invention makes it possible to employ thin- 'ner plate stock'for lthe heads or thetank than would otherwise be possible without danger of'.-

injury'to the enamel from stress at the knuckle A ceramic enamel lining I is` applied and red to the inner surface of the The upper head 42 preferably has anA employed `within the scope of the accompanying claims. The invention is claimed as follows:

v 1. A tank of the class described. comprising a curved pressure-resisting head having a longitudinally extending circumferential ilange with a protective lining of brittle material Ibonded there- 2. In a tank of the class described having a lined circumferentially nanged head inserted in A and circumferentially welded to the end of a gento, a generally cylindrical shell having said head l erally cylindrical shell, a circumferential slot disposed in the flange between the weld 'and the juncture of the ilange with the body of the head V to relieve the latter yof stresses set up by shrinkage of the weld.

3. In a tank of the class described, a ceramic 4 enamel lined head with a longitudinally extending circumferential ange inserted in the end of a generally cylindrical shell, a circumferential weld securing the end of the ange to` the end.

of the' shell. and a circumferential slot cut in the flange on the exposed side opposite the lining at a location closely adjacent the weld and` between it and the main body of the flange.-

' FRANCIS W. LAUCK. 

